Spanners with returning functions are more and more popular currently. Furthermore, ratchetless spanners with returning functions have the advantages of lower noise and easy operation and thus they are the main trend in hand tools.
Current ratchetless spanner has a round cylinder as an ejecting unit in returning operation. The cylinder may cause the driving head to resist against an inner wall of a driving portion. However in this prior art, the round cylinder has an equal diameter in the longitudinal direction. No variation is in the radial direction and thus the positioning of the round cylinder is bad. It easily shifts and thus the positioning effect is not preferred.
Furthermore, since the round cylinder has an equal diameter, it cannot modify in wearing so that the cylinder will deform gradually in use. Thereby the returning function will lose due to the deformation of the round cylinder.